Shielded Metal Arc Welding (SMAW) in Ductile Irons (DI) is often required by foundries for practical manufacturing reasons. The mechanical properties of the welded structures are strongly dependent on their HAZ’s wid...Shielded Metal Arc Welding (SMAW) in Ductile Irons (DI) is often required by foundries for practical manufacturing reasons. The mechanical properties of the welded structures are strongly dependent on their HAZ’s width. A model based on the behaviour of the ferritic matrix of high-Si DIs in order to make an approach in measuring their HAZ’s width is developed in this study. A series of thermal treatments on 3.35 and 3.75 wt% Si as-cast DIs and spot SMAWs is applied on these materials. The applied SMAWs are done on non-preheated and preheated samples (150℃ - 300℃). For welding we modify the amperage (100 - 140A). The micro-hardness Vickers changes in the ferrite of the as-cast samples and inside the HAZ of the welded ones can be attributed to the existence of residual stresses (RS) in the ferritic matrix and assist in estimating the HAZ’s width.展开更多
Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group fr...Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content.展开更多
Triglycine sulfate crystal and potassium bromide doped triglycine sulfate crystals were grown from aqueous solution by slow evaporation method. Energy dispersive X-ray analysis identifies the elements present in the c...Triglycine sulfate crystal and potassium bromide doped triglycine sulfate crystals were grown from aqueous solution by slow evaporation method. Energy dispersive X-ray analysis identifies the elements present in the crystal. The Fourier Transform Infrared spectroscopy has been recorded in the range 400 to 4000 cm-1 and the functional groups of the grown crystals have been identified. The structural studies on the grown crystals were carried out by X-ray diffraction analysis technique and found that the grown crystal crystallizes in monoclinic structure. The lattice cell parameters of pure Triglycine sulfate are a = 9.6010 ?, b = 12.5600 ?, c = 5.4500 ?. Ultraviolet-Visible spectra show that the grown crystals have wide optical transparency in the entire visible region.展开更多
Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and...Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and structure between the S30432 inwall shot-blasting tube produced by Baosteel with six technological process parameters and the imported super 304H were studied systematically by contrast test research.It has been demonstrated that the S30432 obtains a higher residual stress,a deeper distributed layer and a better sub-grain size of the inwall field shot-blasting layer;the martensite content of the shot-blasting surface was low;and micro-hardness and structure refinement were better.After 2000 h’ oxidation test under the 650℃/26MPa steam condition,steam oxidation resistance of the Baosteel steel tube shot-blasting surface was higher,the oxide layer was thinner,and was well combined with bulk material.展开更多
Background: Although many authors advise to postpone surgical intervention until skeletal maturity is reached, the Langenskiöld procedure—entailing physiolysis and the release of Vickers’ ligament—is a kno...Background: Although many authors advise to postpone surgical intervention until skeletal maturity is reached, the Langenskiöld procedure—entailing physiolysis and the release of Vickers’ ligament—is a known procedure in case of Madelung’s deformity in children. Although advised in textbooks and recent reviews, the results and late sequelae of this procedure have been poorly documented. The aim of this study is to portray the late effects of this procedure for three patients and emphasize a very careful patient selection. Methods: A retrospective study was performed of the medical records of three patients who underwent a Langenskiöld procedure with release of Vickers’ ligament for Madelung’s deformity of the wrist. They were recalled for function evaluation and their results are presented in the current study. Results: We report the long term results of three patients (five wrists) who underwent a Langenskiöld procedure with release of Vickers’ ligament in detail. Mean follow-up was twelve years (range: 11 - 14 years). In all of the operated wrists severe pain recurred due to destruction of the distal radio-ulnar joint. Further salvaging surgeries were necessary, some with highly dissatisfying results. Conclusions: Based on our experience we advise not to perform this procedure until further studies have proven its effectiveness and clear indications. Other techniques are available for later correction of Madelung’s deformity, with similar results on pain relief, wrist function and cosmetics. However, we will advocate conservative treatment until skeletal maturity is reached.展开更多
文摘Shielded Metal Arc Welding (SMAW) in Ductile Irons (DI) is often required by foundries for practical manufacturing reasons. The mechanical properties of the welded structures are strongly dependent on their HAZ’s width. A model based on the behaviour of the ferritic matrix of high-Si DIs in order to make an approach in measuring their HAZ’s width is developed in this study. A series of thermal treatments on 3.35 and 3.75 wt% Si as-cast DIs and spot SMAWs is applied on these materials. The applied SMAWs are done on non-preheated and preheated samples (150℃ - 300℃). For welding we modify the amperage (100 - 140A). The micro-hardness Vickers changes in the ferrite of the as-cast samples and inside the HAZ of the welded ones can be attributed to the existence of residual stresses (RS) in the ferritic matrix and assist in estimating the HAZ’s width.
文摘Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content.
文摘Triglycine sulfate crystal and potassium bromide doped triglycine sulfate crystals were grown from aqueous solution by slow evaporation method. Energy dispersive X-ray analysis identifies the elements present in the crystal. The Fourier Transform Infrared spectroscopy has been recorded in the range 400 to 4000 cm-1 and the functional groups of the grown crystals have been identified. The structural studies on the grown crystals were carried out by X-ray diffraction analysis technique and found that the grown crystal crystallizes in monoclinic structure. The lattice cell parameters of pure Triglycine sulfate are a = 9.6010 ?, b = 12.5600 ?, c = 5.4500 ?. Ultraviolet-Visible spectra show that the grown crystals have wide optical transparency in the entire visible region.
文摘Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and structure between the S30432 inwall shot-blasting tube produced by Baosteel with six technological process parameters and the imported super 304H were studied systematically by contrast test research.It has been demonstrated that the S30432 obtains a higher residual stress,a deeper distributed layer and a better sub-grain size of the inwall field shot-blasting layer;the martensite content of the shot-blasting surface was low;and micro-hardness and structure refinement were better.After 2000 h’ oxidation test under the 650℃/26MPa steam condition,steam oxidation resistance of the Baosteel steel tube shot-blasting surface was higher,the oxide layer was thinner,and was well combined with bulk material.
文摘Background: Although many authors advise to postpone surgical intervention until skeletal maturity is reached, the Langenskiöld procedure—entailing physiolysis and the release of Vickers’ ligament—is a known procedure in case of Madelung’s deformity in children. Although advised in textbooks and recent reviews, the results and late sequelae of this procedure have been poorly documented. The aim of this study is to portray the late effects of this procedure for three patients and emphasize a very careful patient selection. Methods: A retrospective study was performed of the medical records of three patients who underwent a Langenskiöld procedure with release of Vickers’ ligament for Madelung’s deformity of the wrist. They were recalled for function evaluation and their results are presented in the current study. Results: We report the long term results of three patients (five wrists) who underwent a Langenskiöld procedure with release of Vickers’ ligament in detail. Mean follow-up was twelve years (range: 11 - 14 years). In all of the operated wrists severe pain recurred due to destruction of the distal radio-ulnar joint. Further salvaging surgeries were necessary, some with highly dissatisfying results. Conclusions: Based on our experience we advise not to perform this procedure until further studies have proven its effectiveness and clear indications. Other techniques are available for later correction of Madelung’s deformity, with similar results on pain relief, wrist function and cosmetics. However, we will advocate conservative treatment until skeletal maturity is reached.
